ats use an ointment of
vaseline 1 ounce, balsam of tolu 5 grains, and sulphate of zinc 5
grains.

DISEASES OF THE NERVOUS SYSTEM.

By M. R. TRUMBOWER, V. S.

[Revised by John R. Mohler, A. M., V. M. D.]

ANATOMY AND PHYSIOLOGY OF THE BRAIN AND NERVOUS SYSTEM.

(Pl. XIX.)

The nervous system may be regarded as consisting of two sets of organs,
peripheral and central, the function of one being to establish a
communication between the centers and the different parts of the body,
and that of the other to generate nervous force. The whole may be
arranged under two divisions: First, the cerebrospinal system; second,
the sympathetic or ganglionic system. Each is possessed of its own
central and peripheral organs.

In the first, the center is made up of two portions--one large and
expanded (the brain) placed in the cranial cavity; the other elongated
(spinal cord), continuous with the brain, and lodged in the canal of the
vertebral column. The peripheral portion of this system consists of the
cerebrospinal nerves, which leave the axis in symmetrical pairs and are
distributed to the skin, the voluntary muscles, and the organs.

In the second, the central organ consists of a chain of ganglia,
connected by nerve cords, which extends on each side of the spine from
the head to the rump. The nerves of this system are distributed to the
involuntary muscles, mucous membrane, viscera, and blood vessels.

The two systems have free intercommunication, ganglia being at the
junctions.

Two substances, distinguishable by their color, namely, the white or
medullary and the gray or cortical substance, enter into the formation
of nervous matter. Both are soft, fragile, and easily injured, in
consequence of which the principal nervous centers are well protected by
bony coverings. The nervous substances present two distinct forms--nerve
fibers and nerve cells. An aggregation of nerve cells constitutes a
nerve ganglion.

The nerve fibers represent a conducting apparatus and serve to place the
central nervous organs in connection with peripheral end organs. The
nerve cells, however, besides transmitting impulses, act as
physiological centers for automatic, or reflex, movements, and also for
the sensory, perceptive, trophic, and secretory functions. A nerve
consists of a bundle of tubular fibers, held together by a dense
areolar tissue, and inclosed in a membranous sheath--the neurilemma.
Nerve fibers possess no elasticity, bu